1. Field of the Invention
The present invention relates to self draining valves which are incorporated in the water lines of underground water distribution systems to automatically drain water from the systems during periods when the water systems are not being used.
2. State of the Art
Underground water distribution systems used in irrigation must be drained during periods of nonuse, especially during periods of freezing conditions. Various means have been used in accomplishing such drainage. Conventional valves can be used to be turned on manually or by an actuator for draining water from the system. To prevent local areas of isolated depressions in the water lines of the system from remaining full of water, air pressure has been used in an attempt to blow all the water from the system.
Automatic, self draining valves have been used in a much improved and more simplified method of draining the water lines. The relatively inexpensive, automatic valves are coupled into the water lines of the system at all low points. When water pressure is turned on in the system, the self draining valves close automatically in response to the water pressure. When water pressure is turned off in the system, the self draining valves automatically open and allow drainage of residual water in the water lines. By draining trapped water from all low spots in the system, damage due to water freezing in the water lines is avoided. Descriptions of representative, automatic, self draining valves is found in the prior patent literature. For example, see U.S. Pat. No. 3,779, 276 and other patents noted therein.
3. Objectives
A principal objective of the invention is to provide novel, improved, automatic, self draining valves which can be inexpensively manufactured and assembled.
Another objective of the present invention is to provide such valves which can be readily disassembled by the user in the field for maintenance purposes as contrasted to the valves of the prior art which are sold as a sealed units and cannot have maintenance performed thereon.
An additional objective of the present invention is to provide such valves which have socket adapters which allow a drain tubes to be connected to the valves for disposal of the drain water released by the valves.
A still further objective of the present invention is to provide a resilient valve head unit having a novel insertion stem for installing the valve head unit within the body of the valves.